Compact Gas Sensor Layout With Ellipsoidal-Plane Light Path
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Solution Overview
Problem
Existing gas sensors, particularly those in the 4R format, face challenges in achieving compactness, cost-effectiveness, and efficient light path optimization, often requiring complex and costly arrangements of reflective surfaces.
Innovation Solution
A gas sensor design utilizing a combination of plane and ellipsoidal reflective surfaces, where odd-numbered surfaces are ellipsoidal and even-numbered surfaces are plane, all supported by a printed circuit board, with light source and detectors on the same board, simplifying manufacturing and reducing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple ellipsoidal reflective surfaces are used to optimize light path, then detection sensitivity is improved, but device complexity and manufacturing cost increase
Solution Approach 1:
The optical path is segmented into multiple reflection stages, with each stage containing a pair of reflective surfaces (one ellipsoidal, one plane) that work together to extend the light path. This segmentation allows the complex function of light path extension to be achieved through simpler, modular reflective pairs rather than a single complex surface arrangement.
Solution Approach 2:
The patent combines ellipsoidal and plane reflective surfaces in alternating pairs to achieve the light path extension function. This merging of different surface types creates a synergistic effect where the ellipsoidal surfaces focus light while the plane surfaces redirect it, achieving high detection sensitivity with a manageable number of components.
2Measurement precision
If multiple reflective surfaces are arranged to maximize light path length, then detection sensitivity is improved, but manufacturing cost increases
Solution Approach 1:
The manufacturing complexity is segmented by dividing the reflective surfaces into standardized pairs mounted on separate substrates. Each pair can be manufactured and tested independently before final assembly, reducing overall manufacturing difficulty and cost while maintaining the extended light path necessary for high sensitivity detection.
Solution Approach 2:
Different reflective surface types (ellipsoidal and plane) are strategically placed at specific locations within the optical path where they provide maximum benefit. This local optimization ensures that each reflective surface contributes efficiently to light path extension, maximizing detection sensitivity while minimizing the total number of surfaces needed and thus reducing manufacturing cost.
3Measurement precision
If light path is extended through multiple reflections, then detection sensitivity is improved, but signal loss increases
Solution Approach 1:
The ellipsoidal reflective surfaces are designed with specific geometric properties that focus light rays onto predetermined paths before they reach the detector. This preliminary focusing action ensures that light remains concentrated and intense throughout the extended optical path, compensating for potential signal loss that would otherwise occur during multiple reflections.
Solution Approach 2:
The alternating pattern of ellipsoidal and plane reflective surfaces creates a reproducible optical path structure that can be precisely replicated. This copying approach ensures consistent light reflection and focusing at each stage, maintaining signal integrity throughout the extended path and minimizing cumulative signal loss.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The design achieves optimized performance with enhanced detection sensitivity and reduced manufacturing complexity, adhering to the 4R format for easy integration into existing electronic systems.
Implementation Method 1
a first-order reflective surface, forming part of an ellipsoid of revolution, having a first focus and a second focus, the first-order reflective surface being positioned opposite the light source, so as to reflect the first cone of light towards the second focus
Implementation Method 2
a measurement photodetector configured to detect a light wave emitted by the light source and propagating through the enclosure
Implementation Method 3
the species composing a gas exhibit different spectral absorption properties. Thus, knowing the spectral absorption band of a gaseous species, its concentration can be determined by estimating the absorption of light passing through the gas, using Beer-Lambert's law
Data Source
Figure 1A~1B
Figure 2A~2B
Figure 3A~3B
AI summary
gas sensor (1) comprising a housing (2), the sensor also comprising: - a light source (10), configured to emit a light wave (11) propagating in the housing, forming, from the light source, a first cone of light (Ω1); - a measurement photodetector (20) capable of detecting a light wave (14) emitted by the light source (10) and having propagated through the housing; - the light source and the measurement photodetector being supported by a printed circuit board (7); a first-order reflective surface, forming part of an ellipsoid of revolution, having a first focus (P1-1) and a second focus (P1-2), the first-order reflective surface being disposed opposite the light source (10), so as to reflect the first cone of light towards the second focus, the first reflective surface forming part of an ellipsoid of revolution.